Means and method of treating wells



June 25, 194-0. L. A. LAYNE 2,2G5,421

MEANS AND METHOD OF TREATING WELLS Filed Oct. 20, 1956 3 Shegts-Sheet l INVENTOR l LE UE A. A N E.

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June 25, 1940. A LAYNE Z Z UEAZI MEANS AND METHOD OF TREATING WELLS Filed Oct. 20, 19256 3 Sheets-Sheen. 2

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L. A. LAYNE MEANS AND METHOD OF TREATING WELLS June 25, 1940.

Filed Oct. 20, 1936 3 Sheets-Sheet 5 YN E E WA E L 5 E L 13. @Me ATTORN EYJ Patented June 25, 1940 PATENT OFFICE MEANS AND METHOD OF TREATING WELLS Leslie A. Layne, Houston, Tex., assignor to The Texas Company, a corporation of Delaware Application October 20, 1936, Serial No. 106,610

4 Claims.

The invention relates to a means and method of treating wells for the purpose of removing un desirable foreign matter from the well and for settling the gravel or filter bed about the strainer in order to provide a better filter bed. In the drilling of wells the formation which is exposed for production is, of course, the perimeter of the well bore, but in many instances it is desirable to obtain a greater exposed area for drainage of the desired fluid into the well bore. To this end the well bores in some instances are enlarged, and, in other instances, after the Well bore has been enlarged, either by under-reaming or washing away the formation by hydraulic pressure, deposits of gravel are made in the well in order to form a drainage or filter bed so that the actual exposed area of the formation is the perimeter of the column of gravel in the well. If desired a screen or other strainer may be disposed in the center of the gravel deposit.

' It is the-practice to deposit this gravel by a carrier fluid such as water or slush and where the Well is drilled by the. rotary method, of course, it is filled with drilling mud or slushat the time the drilling is completed. Under these circumstances the gravel is, therefore, deposited in a body of foreign material which carries some sediment and, of course, there is some intermixing of sand and mud from the formation as well.

It has been found in practice that the usual method of merely circulating water down through the well and outwardly through the strainer or into the well so that it returns to the surface, does not completely wash the gravel or material about the strainer and settle it into a suitable filter bed.

An object is to treat wells by surging a liquid in and out of the area around the well bore.

The present invention concerns itself with pro viding a means and method whereby liquid under pressure and in a large volume may be quickly released into the well bore and forced into the face or wall of the well so that it will move foreign matter which is intermixed with the gravel and also agitate the gravel to some extent so that it will be compacted and form a better filter bed.

It is an object of the invention to provide a surge tank which can be filled with water under fluid pressure so that it can be released quickly into the well bore.

Another object of the invention is to provide a combination of pumps and a surge tank so that a large volume of water under fluid pressure may be turned into the well in order to back wash the gravel.

Another object of the invention is to back wash the gravel in a well by surging a large volume of water under fluid pressure through the gravel.

Another object of the invention is to provide a circulating system for wells so that a pressure may be built up in a surge tank and then released into the well to remove foreign matter from the well bore.

Other and further objects of the invention will be readily apparent when the following description is considered in connection with the accompanying drawings wherein:

Fig. 1 is a side elevation of the apparatus which may be used in practicing the invention and as showing the connection to the well; and

Fig. 2 shows a diagrammatic arrangement of the pumps and the surge tank which may be used in practicing the invention of back washing a Fig.3 shows an arrangement of the well and the pumps used in depositing gravel and back washing the well.

In Fig. 1 the well bore is indicated generally at V 2 and where it enters the producing formation it has been enlarged and a wall or deposit of gravel 3 placed therein about a strainer pipe 4.

There may or may not be a surface casing in the well bore'2, or the pipe 5 may serve as the casing to support the strainer 4 where a full hole setting is made.

Disposed inside of the pipe 5 is the tubing or eduction pipe 1. A suitable packer 9 may be provided about the pipe and inside of the casing 5 so as to form a seal about the eduction tube.

In the form of the invention shown a motor Ill is positioned on the well head. A suitable pump mechanism H is shown as carried by the eduction tube 1 and arranged to be operated by the motor l0.

When the well has been graveled it is the usual practice to either circulate water downwardly into the'well in order to wash the mud and slush therefrom or, if the Well is in condition to produce, the motor In and pump ll may be operated in order to draw liquid into the well from the producing formation. This liquid will, of course, pass through the gravel 3, the strainer 4, and be discharged from the well through the pipe 12. If it is a water well, this Water may be discharged from the outlet valve 14, if desired, and the discharge can be observed so that when it clears up substantially it shows that a majority of themud and sand has been drawn through the gravel. The valve M can be closed, however, and the flow from the pump ll may be directed through the valve l3 and into a tank I5.

This tank'is shown as being portable in trailer form and capable of being moved about by the truck it.

It will be understood that the tank i5 is normally filled with air and that the check valve ill will be closed against outlet but will permit an inflow if the pressure in the tank falls below atmospheric pressure. As the pump it discharges water or the liquid which is being produced by the "well into the tank naturally the pressure increases by virtue of the air in the tank being compressed and the pressure will be indicated by the gauge B8. The tank l5 may be of any size,

shape or configuration, depending upon the circumstances encountered and may or may not be portable.

When the desired pressure has been built up in the tank the motor ill is cut off and naturally there will be a sudden surge of the water back through the valve 53, the pipes l2 and l and into the strainer 6. This surge of liquid is large in volume so that it will discharge through the strainer ii at a relatively high Velocity. This surge of liquid will serve to agitate the gravel 3 and to dislodge any foreign material which is deposited therein and creates a back pressure on the formation. Naturally such liquid will pick up the foreign matter and sediment which it encounters in the gravel and. as soon as the surge ceases the motor in will be started and the pump M will remove this charge of liquid with mud and sand from the well. By opening the valve i l to discharge position the condition of the liquid being pumped from the well may be observed and it may either be discharged and a fresh supply pumped from the well into the tank so that the operation may be repeated, or the same water may bepumped into the tank, as may be found necessary.

It is to be understood that the operation may be repeated as many times as desired, but the principal feature is to churn the sand and gravel in the well by the surge of liquid so that it is washed completely and permitted to settle in a suitable filter bed. In actual practice it has been shown that the production of water wells 22 has been provided and is connected to discharge into the pipe 23 which connects with a T M to the base of the tank l5 and with the Bit pipe l2.

With this arrangement of parts, if desired, the pump 22 may have its suction connected to a suitable source of liquid and may be used to fill the tank l5 either by itself or in combination with the pump II, which is in the well, and operated by the motor II]. In this manner entirely fresh liquid may be pumped into the tank 55 and surged into the well or a combination of fresh liquid and liquid from the well may be used. On the other hand, when the surge into the well is to occur the pump 22 may continue to operate so as to augment the volume of liquid being discharged into the well.

While the motor [0 and pump II have been shown as separate elements they may be combined and any desired type of pump may be used for this purpose. The valve it may be a check valve.

In Fig. 3 a general assembly arrangement is shown where the tank has been omitted and the pump 22 is connected directly to the tube or eduction pipe 1 so that liquid can be pumped into or out of the well bore. Attention is directed to the fact that the casing 38 in this form of the invention may be securely anchored in position by cement 3i and that the head of the casing is sealed by the casing head 32 which may be provided with an outlet 33 controlled by the valve The tubing 7 passes through this casing head 32 and connects with the pipe 62 which carries the valves l3 and i l as described in connection with Fig. 2.

The apparatus for introducing gravel into the well is shown generally at to and includes the pump ill, the gravel tank or container 32 and the series of piping 33 by which pressure may be applied to the inside of the container 52 through the injector or nozzle The discharge pipe 65 connects with the transfer piping it which leads to the gravel line 51 extending down into the well. This gravel line passes through a smiling box Q8 in the casing head and terminates at 19 in the well bore adjacent the elevation where the gravel is to be discharged. The general construction and arrangement of this graveling apparatus is disclosed and claimed in my prior co-pending application, Serial No. 729,025, filed June 4, 1934-, which applicationin turn refers to the disclosure of my Patent 1,975,162, dated October 2, 1934, and also my Patent 2,014,770, dated September 17, 1935. A pulley 55 is adapted to receive a belt by which it may be rotated by a motor it which is offset so that the well head is clear to insert the various equipment.

The screen t has been shown of lesser diameter than the casing 30 and is held in central position by a spider 52 so that the returns from the discharge of the graveling line ll can move upwardly either through the inside of the strainer 4% or through the area 53 between the screen or liner or the casing.

It is understood that with this form of the invention the pumps ii and 22 may be of such size and capacity that they can conduct the operation in a manner similar to the operation described in connection with the use of the tank 55, in Figs. 1 and 2.

The form of the apparatus shown in Fig. 3 is of particular advantage in depositing the gravel in the well because periodically as the gravel is deposited by the graveling line '61 it can be surged or back washed with the pump 22. It will be understood that when the graveling operation is started the lower end 49 of the gravel pipe is closely adjacent the bottom of the cavity and that as the gravel is deposited it chokes up around the lower end of the pipe and indicates to the operator that he should raise the gravel pipe somewhat because he has deposited sufiicient gravel to fill the cavity up to the elevation of the lower end of this pipe. At the time the pipe is raised or whenever desired the pump 22 can be operated to cause a surge down in the well which will tend to settle that gravel which has been deposited and to wash it of foreign material, then when additional gravel has been deposited it can also be washed so that the washing operation is carried on by stages and at the same time the gravel is agitated and settled into a compact'filter bed. The arrangement of Fig.

3 can of course be used with that of Figs. 1 and 2. If the packer 9 is retained the returns could move up through the casing 5 or be taken out by the pump II.

It is to be understood, however, that the surge tank may or may not be used with this combination of apparatus shown in Fig. 3.

Broadly, the invention contemplates a means and method of back washing wells during the development of the well in order to increase its production or to treat a well whose production has decreased due to an accumulation of sand and sediment in the filter bed thereof by applying a surge of any suitable liquid to the well so as to agitate the material making up the filter bed and to remove therefrom the foreign matter, or to release the desirable material so that it may be obtained.

What is claimed as new is:

1. An apparatus for washing wells comprising in combination with the well and a pump therefor of a pressure tank, piping. connecting the well through said pump to said tank, a discharge valve in said piping, said pump being adapted to pump liquid from the well into said tank to increase the pressure therein when said valve is closed whereby the volume of liquid and pressure of fluid in said tank will surge into the well when the pump is stopped.

2. A surge apparatus for washing and agitating wells which comprises a pressure tank, means to build up a pressure in said tank, means to direct a surge of liquid under fluid pressure from said tank into the well, said first means including a pump in the well, and an independent pump both of which'may discharge into said tank.

3. An apparatus for agitating the formation about a well strainer in a well bore which comprises a portable pressure tank adapted to be connected to the well, means to discharge liquid from the well into the tank to compress the fluid normally therein, and means to direct the liquid from the tank back into the well bore to dislodge the formation and remove the finer particles of material therefrom.

4. A method of developing a well having a screen and tubing therein with a wall of gravel deposited about the screen which includes the steps of pumping the well to initiate the flow therefrom and to remove some of the foreign matter and sediment from the gravel, continuing the pumping operation and directing the flow into a closed tank, whereby the fluid in the tank is compressed by the liquid, stopping the pumping operation and releasing the liquid under fluid pressure from the tank into the well screen so that it may discharge through the screen into the wellbore to agitate the gravel wall and to dislodge the accumulations of foreign matter from the gravel.

LESLIE A. LAYNE. 

